Thiols׳ extraction from “jet-fuel” assisted by ionic liquids in hollow fibre membrane contactors

• Alternative process for current expensive jet-fuel desulfurization.
• Integrated extraction/stripping with ionic liquid in hollow fibre membrane contactors.
• Thiol successfully extracted from jet-fuel model stream.
• Efficient ionic liquid regeneration and reuse, by sweep gas stripping.

This work proposes an alternative technique for the selective extraction of thiols from a “jet-fuel” model stream, using the 1-ethyl-3-methylimidazolium triflate ([C2mim][CF3SO3]) ionic liquid as extractant, in a hollow fibre membrane contactor. Due to the low distribution ratio of the thiol towards the ionic liquid, observed in single extraction, a regeneration step (stripping with vacuum or a sweep gas) was added to the extraction process, in order to maximize the concentration gradient overcoming thermodynamic constraints. The stripping with a sweep gas allowed for a complete regeneration of the ionic liquid producing a jet-fuel with sulphur content lower than 2 ppm. Since the controlling step of the process is the extraction of thiol from the feed phase to the ionic liquid phase, the increase of the ionic liquid velocity and operating temperature may further enhance the process performance. The results obtained along with the ultra-low sulphur jet-fuel model produced prove the high potential of this integrated process as an alternative method for replacing the current expensive desulphurization process.